CREATE TABLE t1(a, b, c);
CREATE TABLE t2(d, e, f);
BEGIN;
INSERT INTO t1 VALUES(1,  'one',   'I');
INSERT INTO t1 VALUES(3,  NULL,    NULL);
INSERT INTO t1 VALUES(5,  'five',  'V');
COMMIT;
CREATE INDEX i1 ON t1(a);
CREATE INDEX i2 ON t2(d DESC, e COLLATE REVERSE ASC);
CREATE INDEX i2 ON t1(b);
SELECT a, b FROM t1 UNION SELECT d, e FROM t2;
SELECT a, b FROM t1 INTERSECT SELECT d, e FROM t2;
SELECT a, b FROM t1 EXCEPT SELECT d, e FROM t2;
SELECT a FROM t1 UNION ALL SELECT d FROM t2 ORDER BY 1 LIMIT 5;
